This invention pertains to a system and method for the manufacture of cranial remodeling orthoses for correction of cranial abnormalities.
An infant""s head is commonly misshapen as a result of head molding from the birthing process. The shape gradually improves to a normal shape within the first six weeks of life. However, many infants, i.e., approximately one in 250, exhibit abnormal head shape which without intervention does not return to normal shape.
One such abnormal head shape is known as positional plagiocephaly. Infants with positional plagiocephaly may exhibit complex multistructural asymmetry affecting the cranial vault, face and skull base or facial expression. These head shape deformations may result from environmental factors such as premature birth, restrictive intrauterine environment, birth trauma, cervical anomalies, sleeping position, lack of full bone mineralization, neurological deficits or from the interaction of any of these or other factors.
Surgery of the cranial vault is a commonly used treatment for significant plagiocephaly. However, it has been difficult with surgery to obtain the desired permanent correction in growing infants. As a result of these difficulties, external orthotic devices have been developed which can be used to provide non-invasive, non-surgical correction of cranial abnormalities. Such orthoses have been developed to correct plagiocephaly as well as other cranial abnormalities such as brachycephaly and scaphocephaly. The orthosis device takes advantage of the growing, soft skull of an infant. The orthosis device restrains growth at the protusions in the skull and allows for growth where needed.
In our prior U.S. Pat. No. 5,094,229 issued Mar. 10, 1992, for xe2x80x9cCRANIAL REMODELING ORTHOSISxe2x80x9d and U.S. Pat. No. 5,308,312 issued May 3, 1994, for xe2x80x9cCRANIAL REMODELING ORTHOSISxe2x80x9d we described non-invasive orthosis devices which are of thermoplastic construct comprised of a semi-rigid styrene outer shell thermobonded to a medium durometer polyurethane foam inner lining.
In the past, others have attempted to develop and utilize standardized, off the shelf types of orthoses. It is our belief that the current state of such standardized orthoses is such that they do not represent a desired approach to the correction of highly individualized and unique abnormalities. Because the abnormalities which are to be corrected are unique for each infant, standardized off-the-shelf cranial remodeling bands are ineffective for treatment of most cranial abnormalities.
We have determined that to be effective, the cranial remodeling device must be a custom device which is specially constructed for each infant patient. These devices are fabricated from a plaster of Paris impression taken from an infant patient""s head. This impression or negative is filled with a plaster slurry to create a positive mold which is an exact reproduction of the infant""s head. A highly talented and skilled orthotist or clinician then constructs a second or corrected head mold by filling in areas on the first mold to produce a mold which is of the desired head shape. The orthosis device is then created over the corrected mold. The correction included in forming the corrected mold is based on clinical experience as well as objective anthropomorphic measurements. In the process for producing orthosis devices described in the aforementioned patents, a highly skilled specialist, i.e., an orthotist, modifies the initial positive mold of the patient""s head. The modifications are based in large part upon the specialist""s experience and skill.
To obtain the desired cranial remodeling results requires a course of treatment in which may require fabrication of more than one orthosis for an infant patient. Various factors influence the decision to use more than one orthosis. These factors may include the age of the patient at the start of treatment, the degree of severity of cranial abnormality, and the rate of cranial growth. In addition, it may be necessary to change the initial orthosis design during the course of treatment. For instance, a helmet shaped orthosis may be used initially and the final orthosis may be in the shape of a band.
The technique of utilizing a plaster of paris impression of the patient""s head provides an extremely accurate reproduction of the patient""s head. However, the results of the technique are highly dependent on the skill of the specialist clinician.
In some instances, cranial remodeling orthoses may be utilized as a post surgical treatment.
It is one object of the present invention to provide a system and method which will make the availability of individually customized cranial remodeling orthoses much more widespread.
It is still a further object of the present invention to provide a system and method of fabricating orthoses in which the fabrication of the orthoses is less dependent upon the skill of an orthotist or clinician to produce acceptable results.
The foregoing and other objects are accomplished by the system and method of the present invention.
In a system in accordance with the principles of the invention, the patient""s head is scanned utilizing a scanner. The scanner generates data representative of the surface shape of the patient""s head.
In accordance with the invention, the scanned data is supplied to an automatic milling machine which will produce a positive mold of the patient""s head from which the clinician can produce the corrected mold.
Alternatively, the scanner data can be used by a computer to generate a display of the scanned head in a three dimensional view on the computer display. A clinician can then modify the three dimensional graphic to produce a corrected image of the patient""s head. The computer generated corrected image is then utilized to generate a data file. The data file may be transmitted to the milling machine to produce a corrected positive mold of the patient""s head.
Alternatively, the data file may be utilized to produce the design of a cranial remodeling orthosis which will correct the cranial abnormality of the patient. Automated equipment is utilized to produce the orthosis based upon the information contained in the data file.
Still further in accordance with the principles of the invention, the computer operates on the scanned data along with client specific data which specifies anthropomorphic information relative to the patient. The computer generated data can be utilized to form a mold of the patient""s head from which an orthosis can be molded, or the data can be utilized to control the operation of a fabrication apparatus which will directly produce the orthosis.